package v2ch09.verifier;

import java.applet.*;
import java.awt.*;

/**
 * This application demonstrates the bytecode verifier of the virtual machine. If you use a hex
 * editor to modify the class file, then the virtual machine should detect the tampering.
 *
 * @author Cay Horstmann
 * @version 1.00 1997-09-10
 */
public class VerifierTest extends Applet {
	public static void main(String[] args) {
		System.out.println("1 + 2 == " + fun());
	}
	
	/**
	 * A function that computes 1 + 2.
	 *
	 * @return 3, if the code has not been corrupted
	 */
	public static int fun() {
		int m;
		int n;
		m = 1;
		n = 2;
		// use hex editor to change to "m = 2" in class file
		int r = m + n;
		return r;
	}
	
	public void paint(Graphics g) {
		g.drawString("1 + 2 == " + fun(), 20, 20);
	}
}
